Contributions of disease severity and perceptions of primary and secondary control to the prediction of psychosocial adjustment to Parkinson's disease.

Seventy-four people with Parkinson's disease (PD) completed questionnaires and were interviewed to determine the degree to which the severity of PD and perceptions of primary and secondary control over PD predicted psychosocial adjustment. Significant unique contributions to PD-related participation restrictions were made by disease severity (positive relationship) and perceived internal secondary control (negative relationship). Also, participation restrictions had a significant direct effect, and disease severity and perceived internal secondary control significant indirect effects, on both depressive symptomatology and life satisfaction. Results are consistent with theories that suggest the importance of enhancing internal secondary control processes in situations in which actual control over objective circumstances is limited, such as with chronic and progressive diseases like PD.